Apparatus for plugging well bores with hardenable fluent substances

ABSTRACT

As a preferred embodiment of the apparatus of the present invention disclosed herein, a tubular bag mounted around an elongated tool body is operatively arranged to be expanded into engagement with a well bore wall by filling the bag with a hardenable fluent substance initially contained in a selectivelyoperable displacement assembly releasably coupled to the body. Biasing means are operatively arranged for imposing opposed axial forces against the ends of the expanded bag to securely anchor the tool until the fluent substance has solidified. Once sufficient time has elapsed for the fluent substance to solidify, a uniquely-arranged valve member is moved into seating engagement within a bypass passage provided in the body for blocking further fluid communication between the well bore intervals above and below the tool. One or more pressure-responsive metallic sealing elements are cooperatively arranged on the valve member to effect a permanent seal between the valve member and its associated valve seat.

United States Patent 1 Urbanosky 1 3,750,750 1 Aug. 7, 1973 [54] APPARATUS FOR PLUGGING WELL BORES WITH HARDENABLE FLUENT SUBSTANCES [75] Inventor: Harold J. Urbnnosky, Pearland, Tex.

[73] Assignee: Schluniberger Technology Corporation, New York, N.Y.

[22] Filed: Apr. 5, 1972 [21] Appl. No.: 241,154

[52] US. Cl. 166/187, 166/188 [51] Int. Cl E2lb 33/127 [58] Field of Search 166/187, 188, 133

[56] References Cited UNITED STATES PATENTS 2,196,658 4/1940 Burt 166/187 3,460,618 8/1969 Blagg 166/187 3,460,624 8/1969 Aitken et a1. 166/187 3,460,625 8/1969 Hart et al 166/187 3,556,215 1/1971 Owens 166/187 3,578,079 5/1971 Alexander... 166/187 3,578,083 4/1971 Anderson.... 166/187 3,666,011 5/1972 Owens 166/187 Primary Examiner-James A. Leppink Attorney-Ernest R. Archambeaui, Jr. et al.

[57] ABSTRACT As a preferred embodiment of the apparatus of the present invention disclosed herein, a tubular bag mounted around an elongated tool body is operatively arranged to be expanded into engagement with a well bore wall by filling the bag with a hardenable fluent substance initially contained in a selectively-operable displacement assembly releasably coupled to the body. Biasing'means are operatively arranged for imposing opposed axial forces against the ends of the expanded bag to securely anchor the tool until the fluent substance has solidified. Once sufficient time has elapsed for the fluent substance to solidify, a uniquely-arranged valve member is moved into seating engagement within a bypass passage provided in the body for blocking further fluid communication between the well bore intervals above and below the too]. One or more pressureresponsive metallic sealing elements are cooperatively arranged on the valve member to effect a permanent seal between the valve member and its associated valve seat.

22 Claims, 7 Drawing Figures tan-50.150

Pmnzowc ms FIG. 5

APPARATUS FOR PLUGGING WELL BORES WITH ,IIARDENABLE FLUENT SUBSTANCES In various well-completion operations it is often desired to place a fluid-tight barrier or plug at a desired location in a well bore below the lower end of substantially-smaller well pipe or tubing string. It will, of course, be appreciated that conventional bridge plugs that are small enough to pass through a small-diameter tubing string are incapable of being expanded to a diameter equal to that of the well bore which may be 2 to times greater than the tubing diameter. Accordingly, so-called through-tubing bridge plugs such as those shown in US. Pat. No. 3,556,215, US. Pat. No. 3,578,079 and 11.8. Pat. No. 3,578,083 as well as the patents mentioned therein are typically employed for situations of this nature.

As illustrated in the aforementioned patents, these through-tubing bridge plugs generally include a fluiddisplacement device that is supported by a suspension cable and releasably coupled to an elongated body member therebelow carrying an expansible tubular bag that is initially retained in a collapsed position. Once the tool has passed through a reduced-diameter tubing string and isin the enlarged well bore below the lower end of the tubing string, a fluent substance such as a hardenable plastic or cernentitious composition is selectively discharged from the displacement device into the expansible bag so as to firmly expand the bag into sealing contact with the walls of the well bore therearound. Thereafter, once the hardenable substance within the expanded bag has hardened, the well bore will be tightly plugged so as to prevent fluid or pressure communication between the well bore intervals above and below this barrier. i i a It will, of course, be appreciated that until the fluent substance has completely hardened, the bag and at least the lower portions of the tool carrying the expanded bag must be secured against movement upwardly or downwardly in the well bore. Accordingly, as described in the aforementioned patents, a fluid bypass passage is typically provided through the tool body for equalizing the pressures above and below the expanded bag as well as for accommodating at least a substantial quantity of any flowing well bore fluids during the time that the fluent material is hardening. After the fluid substance has hardened, this bypass passage is closed, hopefully permanently, to complete the formation of the fluid-tight well bore barrier, 1

Although these well-completion tools have met with considerable commercial success, the problem of permanently blocking the bypass passages in the tools has still not been fully solved heretofore. For instance, those skilled in the,art,willlappreciate, that with a typical. valve arrangement such as that shown in US. Pat. No. 3,556,215, the permanenceof the closure of the bypass passage is wholly dependent upon. the durability of the sealing members which are typically arranged (as at 96" and 97" in that patent) around. the body of the movable valve member. The usualpractice heretofore has, of course, beento use O-rings of a somewhatresilient material, such. as an elastomer, for these sealing members. It will be recognized, however, that, in time, such. materials are degraded or even deteriorated by extreme well bore temperatures as well as. corrosive well bore fluids. Thus, even thoughcorrosionresistant materials can be utilized; in the other parts of these through-tubing bridge plugs, the useful life of such a tool is no longer than that of these critical sealing members.

Accordingly, it is an object of the present invention to provide new and improved apparatus adapted for plugging a well bore with an initially-fluent hardenable substance and including a body having a bypass passage arranged therein whichis selectively closed after the substance has hardened and will remain permanently blocked without subsequent deterioration or degradation by adverse well bore conditions or corrosive well bore fluids. i

This and other objects of the present invention are attained by providing an extendible wall-engaging supporting member which iscooperatively arranged on a body to be extended outwardly toward a well bore wall for supporting an initially-fluent hardenable substance until the substance is hardened around the body to plug the well bore. Bypass control means are cooperatively arranged on the body to provide an initially-opened fluid passage and include selectively-closable valve means including a valve seat in the passage and a valve member having at least one expansible metallic sealing member cooperatively arranged therearound for expansion into seating engagement betweenthe valve seat and valve member in response to a pressure differential acting in at least'one direction acrossthe valve member once it is moved to a passage-closing,position.

The novel features of the present invention are set forth with particularity in the appended claims. The invention, togetherwith further objects and advantages thereof, may be best understood by way of the following description of exemplary apparatus employing the principles of the invention as illustrated in the accompanying drawings, in which: i a

FIG. 1 depicts a preferred embodiment of a wellcompletion tool arrangedin accordance with. the principles of the present invention as the tool is being lowered through a tubing string to a desired location in a well bore;

. FIGS. 2A2C are successive cross-sectional elevational views of the new andimprovedtool depicted in FIG. 1 illustrating the initial positionsof the various elements thereof before the tool has been actuated;

FIG. 3 depicts the tool shown in FIG. 1 after it has set in position within a well bore; and i I FIGS. 4 and 5 are enlarged views of a portion of the bypass control means of the present invention. Turning now to FIG. 1, a well-completion tool .10 incorporating the principlesof the present inventionand dependently supported by a suspension cable 11 is depicted as'it is being lowered through a string of tubing 12 toward a selected position below the lower end of the tubing string within a larger-diameter well, bore 13 which, in this instance, iscased as at 14. If desired, a typical casing collar locator 15 may be incorporated with the tool 10 for determining the depth at which the toolis to be halted.

In the preferred embodiment depicted, the wellcompletion tool .10 includes selectively-operable .fl'uiddisplacement means 16 arranged in an upper section 17 thereof and carrying asupplyof an initially-fluent hardenable material which, upon command from the surface, is selectively displaced into extendible,.walladapted for supporting the fluent substance until it hardens into a solidified mass. As will subsequently be explained in detail, biasing means 20 carried on the body 19 are arranged for selectively imposing opposed axial forces against the ends of the expanded bag 18 to anchor the tool once the tubular bag has been filled with a sufficient quantity of the fluent substance to expand it outwardly into sealing engagement with the well casing 14. The upper section 17 of the tool 10 is then released from the lower body and returned to the surface. Thereafter, once sufficient time has elapsed for the fluent substance to adequately harden so as to form an impermeable transverse barrier or a bridge plugging the well casing 14, new and improved bypass control means 21 mounted on the lower end of the body 19 are operatively arranged for permanently closing a bypass passage 22 in the body of the tool 10 which is temporarily left open for equalizing pressure differentials acting across the inflated bag 18 until the fluent substance therein has hardened.

Turning now to FIGS. 2A-2C, a cross-sectioned elevational view is shown of the new and improved wellcompletion tool 10 as it appears before the collapsed bag 18 carried thereon is expanded. The upper section 17 of the tool 10 is operatively arrangedfor carrying a substantial volume of an initially-fluent, hardenable substance 23 which, upon operation of the selectivelyoperable fluid-displacement means 16, is forcibly displaced into the tubular bag 18 to expand it outwardly into sealing engagement with the well casing 14. Accordingly, the upper housing section 17 of the tool 10 is arranged to provide an enlarged chamber 24 in its upper portion that is joined by an axial passage 25 to an enlargeddiameter longitudinal bore 26 extending substantially the full length of the housing section and terminating at its lower end. The upper portion of the elongated body 19 is also enlarged and similarly provided with an enlarged diameter longitudinal bore 27 which extends upwardly to the upper end of the body. The adjacent ends of the housing 17 and the body 19 are complementally fitted together and fluidly sealed as at 28, with the two members being releasably coupled to one another by latching means 29 so that their bores 26 and 27 define a combined fluid chamber 30 of substantial length and volumetric capacity.

' The fluid-displacement means 16 include a piston 31 operatively arranged in the fluid chamber 30 so as to be initially positioned just above the upper surface of the fluent substance 23. In this manner, upon downward movement of the piston 31, the fluent substance 23 will be displaced from the fluid chamber 30 and into the expansible bag 18 mounted on the body 19 therebelow. It will, of course, be appreciated that by providing lateral ports, as at 32, in the housing section 17, well bore fluids will be admitted into the longitudinal housing bore 26 for maintaining the space above the piston 31 as well as the fluent substance 23 in the fluid chamber 30 at the hydrostatic pressure of the well bore fluids.

In the preferred manner of moving the displacement piston 31 downwardly, the fluid-displacement means 16 further include a cylindrical weight 33 initially disposed in the enlarged bore 26 immediately above the piston and releasably supported therein by two or more upwardly-extending, inwardly-biased latch fingers 34 arranged on an upright rod 35 on the upper end of the weight. As illustrated in FIG. 2A, the latch fingers 34 have outwardly-enlarged heads 36 which are adapted to be received in an enlarged portion 37 of the axial housing passage 25 immediately above the upper end of the enlarged-diameter longitudinal bore 26. In this manner, so long as the latch fingers 34 are laterally separated, their respective enlarged heads 36 are supported on the upwardly-directed shoulder 38 defined at the lower end of the recess 37. To retain the latch fingers 34 initially separated from one another, an actuating piston 39 is disposed in the chamber 24 and coupled to a depending axial rod 40 which extends through the axial passage 25 into the enlarged recess 37 so as to be interposed between the opposed heads 36 of the latch fingers so long as the actuating piston is not further elevated by a compression spring 41 mounted within the enlarged chamber.

To retain the actuating piston 39 in its initial lower position depicted in FIG. 2A, the upper portion of the chamber 24 is initially filled by a relatively noncompressible fluid such as water or oil; and this fluid is retained therein so long as a normally-closed solenoid valve 42 connected to suitable electrical conductors 43 in the cable 1 1 is not operated to open communication by way of a fluid passage'44 between the enlarged chamber and the exterior of the tool 10. Accordingly, it will be appreciated that once the upper end of the chamber 24 has been filled with a sufficient volume of hydraulic fluid to shift the actuating piston 39 downwardly to its illustrated position, the depending rod 40 thereon will be positioned between the opposed enlarged heads 36 for maintaining the weighted body 33 releasably suspended just above the displacement piston 31.

In one manner of arranging the latching means 29, the lower end of the housing section 17 is adapted to r be complementally received within the upper end of the enlarged longitudinal bore 27 in the elongated body 19. An inwardly-opening circumferential groove 45 formed around the wall of the internal bore 27 is adapted for receiving outwardly-enlarged heads 46 on the lower ends of two or more yieldable latch fingers 47 dependently mounted on the lower end of the upper housing section 17. A ring 48 is normally positioned in the longitudinal bore 27 to the rear of the enlarged heads 46 and suitably dimensioned to retain the'enlarged heads within the circumferential groove 45 until the ring is shifted downwardly in relation to the heads. To retain the ring 48 in its depicted elevated position, an upstanding support 49 is coupled thereto and extended upwardly into the lower end of the housing section 17. An annular plate 50 is mounted around the upper end of the support 49 and slidably arranged within an inwardly-facing recess 51 within the bore 26 and supported therein by a spring 52 which normally urges the annular plate upwardly against the downwardly-facing surface at the top of the recess.

In this manner, so long as the annular plate 50 is elevated as depicted in FIG. 2A, the latch ring 48 is engaged with the reverse side of the enlarged heads 46 to retain them within the circumferential housing groove 45 and, thereby, securely latch the tool sections 17 and 19 together. It will be appreciated, however, that upon downward travel of the displacement piston 31 through the enlarged housing bore 26, the piston will ultimately contact the annular plate 50 and shift it downwardly a sufficient distance to displace the latch ring 48 below the enlarged heads 46 so as to permit the upper tool section 17 to be uncoupled from the elongated body 19 by simply pulling on the suspension cable 11.

, To initially retain the fluent substance 23 within the fluid chamber 30, the lower end of the enlarged longitudinal body bore 27 is normally closed by an annular valve member 53 that is slidably arranged and fluidly sealed, as at 54, within the lower end of the enlarged body bore. To normally secure the valve member 53 in its depicted elevated position, a shear pin 55 is arranged to releasably secure the valve member to the elongated body 19 until the fluid pressure of the fluent substance 23 has been increased sufficiently to break the shear pin and shift the valve member downwardly.

For reasons that will subsequently become apparent, an elongated tubular member 56 is coaxially supported within the elongated body bore 27 and terminated at its upper end by one or more lateral outlets 57 to provide communication between the upper end of the tubular member and the exterior of the tool 10. By providing an enlarged-diameter portion 58 on the tubular member 56 immediately adjacent to the normal elevated position of the annular valve member 53 and arranging a sealing member 59 thereon for engagement within the axial bore of the annular valve member, the fluent substance 23 thereabove cannot be displaced from the fluid chamber 30 until the annular valve member has moved downwardly a sufficient, distance to bring its upper end below the sealing member 59.

The intermediate portion of the elongated body 19 is sufiiciently reduced in diameter to accommodate a pair of longitudinally-spaced collars 60 and 61 which are respectively slidably mounted and fluidly sealed, as at 62 and 63, around the reduced-diameter portion of the body and secured, as by bands 64 and 65, within the opposite ends of the elongated tubular bag 18 which is preferably formed of a suitable wear-resistant, flexible and fluid-impervious material, such as a Dacron cloth impregnated with Neoprene, that does not readily stretch. The bag 18 is, therefore, formed with an expanded diameter corresponding generally to that of the well casing 14; and, preferably, is folded around the intermediate portion of the body 19 in such a manner as to minimize its lateral dimensions and lightly tied in this collapsed position by string or tape. In its initiallycollapsed position illustrated in FIG. 2B, the tubular bag 18 is drawn to its full length with the slidable collars 60 and 61 at their most-widely separated positions along the body 19; and the upper collar is releasably secured in its initial position by one or more upright latch fingers 66 which areinwardly biased to retain enlarged heads 67 thereon in a circumferential groove 68 around the body.

It will be noted that by virtue of the sealing members 62 and 63 on the slidable collars 60 and 61, the interior of the bag 18 defines a fluid-tight space around the body 19. Accordingly, to provide communication within the collapsed bag 18, one or more lateral ports 69 are arranged in the reduced-diameter portion of the body 19 at a location between the depicted elevated position of the upper collar 60 and the lower position towhich the collar will slide downwardly when the bag is initially expanded. The lower end of the elongated tubular member 56 is extended below the ports 69 and sealingly engaged, as at 70, within the longitudinal bore a 71 through the reduced portion of the body 19. Thus, so long as the upper collar 60 is retained in its initial elevated position by the latch fingers 66, once the valve member 53 is shifted downwardly, the fluent substance 23 released from the fluid chamber 30 will be directed through the annular space between the body 19 and the lower portion of the tubular member 56 and into the bag 18 by way of the lateral ports 69.

It will, of course, be appreciated that once the upper collar 60 has been carried downwardly (as will subsequently be described) a sufficient distance to position the sealing member 62 on the collar below the lateral ports 69, the fluent substance 23 confined in the interior space within the expanded bag 18 will be trapped therein. For reasons that will subsequently be explained, a second circumferential groove 72 is formed around the reduced-diameter portion of the body 19 just below the lateral ports 69 so that, once the collar 60 has shifted downwardly in relation to the ports, the enlarged heads 67 on the latch fingers 66 will engage this lower circumferential groove: to prevent the upper collar from subsequently moving upwardly from it lower position.

The selectively-operable biasing means 20 are preferably arranged on the elongated body 19 somewhat below the lower collar 61; As illustrated in FlGS. 2B and 2C, in the preferred manner of arranging the biasing means 20, an annular member 73 is slidably mounted around the reduced portion of the elongated body 19 and adapted to be moved upwardly thereon by a stout compression spring 74 carried on an upwardly- .directed body shoulder 75 and engaged with the lower end of the slidable annular member. For reasons that will subsequently be explained, the spring 74 is initially retained in compression by one or more ball members 76 that are respectively arranged in lateral recesses 77 spaced around the annular member 73 and sized for partial reception in a circumferential groove 78 formed around the intermediate portion of the body 19. A sleeve member 79 is coaxially mounted around the annular member 73 and has its lower portion formed with an internal diameter appropriately sized in relation to the diameter of the balls 76 and the depth of the circumferential groove 78 to prevent outward lateral movement of the balls from the groove so long as the ball-retainer sleeveremains in the elevated position illustrated in FIG. 2B. i

To permit outward movement of the balls 76 from the circumferential groove 78, longitudinal grooves or slots 80 are arranged in the upper'portion of the ballretainer sleeve 79. Thus, upon downward movement of the retainer sleeve 79 in relation to the annular member 73 to bring the slots 80 respectively into registration with the several balls 76, the upwardly-directed force of the compression spring 74 will be effective for shifting the annular member 73 upwardly in relation to the elongated body 19 once the balls are. shifted outwardly out of the circumferential body groove 78 and into the enlarged space provided by the elongated slots. In this manner, it will be appreciated that once the ballretainer sleeve 79 is moved downwardly against the restraint of a relatively-weak compression spring 81 mounted between the retainer sleeve and the annular member 73, the stout compression spring 74 will be freed for shifting the annular member upwardly against the lower slidable collar 61. To provide for the actuation of the ball-retainer sleeve 79, the lower portion of the lower collar 61 is appropriately sized, as at 82, to engage an inwardly-turned lip 83 on the upper end of the ball-retainer sleeve for shifting the retainer sleeve downwardly in relation to the annular member 73 for releasing the balls 76 from the circumferential body groove 78.

As previously mentioned, the normally-open bypass passage 22 is provided for reducing, if not altogether equalizing, pressure differentials existing across the expanded bag 18 as the fluent substance 23 therein is hardening. Accordingly, as shown in FIG. 2C, one or more lateral ports 84 are formed in the elongated tool body 19 well below the depicted initial position of the lower collar 61. In this manner, the bypass passage 22 through the body 19 between the upper and lower ports 57 and 84 is defined by the tubular member 56 and the intermediate longitudinal body bore 71 below the lower end of the tubular member. To selectively close this bypass passage 22, the new and improved bypass control means 21 are preferably arranged to include a valve member 85 including a tubular valve body 86 having longitudinally-spaced sealing members 87 and 88 thereon which is operatively disposed within the longitudinal body bore 71 for movement upwardly by valve-actuating means 89 from an initial lower position immediately below the lateral ports 84 to a final elevated position (as defined by a downwardly-facing shoulder 90 in the longitudinal bore) where the valve member is adjacent to the lateral ports with its sealing members respectively spanning the ports and sealingly engaged with a valve seat 91 defined in the body 19 above and below the ports. Thus, in its initial position, the bypass control means 21 provide fluid communication through the bypass passage 22 and the ports 57 and 84 for accommodating at least a substantial proportion of any well bore fluids moving upwardly and downwardly past the well-completion tool during the time that the fluent substance 23 is hardening within the expanded bag 18. The details of the valve mem ber 85 will be subsequently explained by reference to FIGS. 4 and 5.

In the preferred manner of selectively. closing the valve member 85 of the bypass control means 21, the valve-actuating means 89 include an elongated tension spring 92 which has its upper end anchored, as by a transverse rod 93 (FIG. 28), to the intermediate portion of the body 19 and has its remaining portion extended downwardly therefrom through the longitudinal body bore 71 (FIG. 2C). The spring 92 is terminated by a long straight portion 94 which is passed through the valve body 86 and releasably secured in an initiallystretched condition by means of a hook 95 that is coupled to a wire or cord 96 releasably secured to a geared timer mechanism 97 enclosed in an enlarged oil-filled chamber 98 in the lowermost portion of the tool body In one manner of arranging the timer mechanism 97, the rotational speed of the uppermost gear 99 therein is regulated by a train of gears that is terminated by a paddle-like wheel member 100 that is driven by the force of the spring 92 acting through the gear train. Thus, by releasably coupling the cord 96 to the shaft 101 carrying the upper gear 99 of the gear train and winding the wire or cord therearound, the tension force of the spring 92 will be effective for slowly rotating this uppermost gear at a speed which, by virtue of the gear train, is regulated by the faster, but retarded, rotational speed of the rotating paddle member 100 in the oilfilled chamber 98. Accordingly, once the cord 96 is wound around the shaft 101 and coupled to the hook 95 on the lower end of the spring 92, a preselected time interval will be provided before a transverse member, such as a washer 102, loosely mounted on the straight portion 94 of the spring is moved upwardly to shift the valve member upwardly into the seat 91 to close the ports 84. In other words, once the cord 96 is connected, the tension force of the spring 92 will begin slowly unwinding the cord from the shaft 101 so that, once the gear 99 has been rotated a sufficient number of revolutions to unwrap the cord therefrom, the lower end of the cord will be released from the shaft and the spring will then jerk the washer 102 upwardly to carry the valve member 85 into its final port-closing position.

To preparethe new and improved well-completion tool 10 for operation, the fluid chamber 24 above the weight-releasing piston 39 is filled with a sufficient volume of hydraulic fluid to shift the piston against the spring 41 to a position where the depending rod 40 extends downwardly into the recess 37. The weighted body 33 is forced upwardly, compressing a coil spring 103 thereabove until the enlarged heads 36 of the latch fingers 34 are within the recess 37 on opposite sides of the lower end of the rod 40 and are supported on the shoulder 38 for retaining the weighted body 33 in its elevated position above the fluid-displacement piston 31. The lower end of the upper housing 17 is complementally fitted into the upper end of the upper portion of the elongated tool body 19 and the latch ring 48 is properly positioned to retain the enlarged heads 46 in the internal circumferential groove 45. The upper valve member 53 is secured in its upper or closed position by the shear pin 55; and the enclosed fluid chamber 30 is then filled with a suitable plastic or cementitious initially-fluent substance 23 which will harden into a solid mass that preferably expands slightly as it fully hardens.

The annular member 73 is shifted into position on the intermediate portion of the tool body 19 so as to place the balls 76 in the groove 78 and releasably retain the compression spring 74 in a compressed condition. The tension spring 92 is extended and the hook thereon is connected to the release cord 96 which has been wrapped several times around the shaft 101 of the upper gear 99 of the timer mechanism 97. As previously mentioned, the predetermined delay before the bypass passage 22 is closed is determined by the number of turns or wraps of the cord 96 around the shaft 101. This time interval is, of course, selected so that the valve member 85 will not be actuated until some time later which is calculated to be sufficient to permit the initially-fluent substance 23 to have at least substantially hardened.

The tool 10 is then lowered into the well bore 13 by means of the suspension cable 11. Once the wellcompletion tool 10 has emerged from the lower end of the tubing string 12 and has reached a selected position therebelow, an electrical signal is sent through the cable conductors 43 to actuate the solenoid valve 42. As previously explained, once the solenoid valve 42 is opened, the hydraulic fluid within the upper chamber 24 will be displaced therefrom by way of the nowopened passage 44 as the compression spring 41 forcibly shifts the weight-releasing piston 39 upwardly. It will be appreciated, of course, that by providing a lateral port 104 in the lower portion of the chamber 24, the weight-releasing piston 39 will be moved upwardly by the spring 41 without restraint from an unbalanced pressure force that would otherwise occur upon opening of the solenoid valve 42 to open the enclosed chamber 24 to the well bore fluids. Once the weightreleasing piston 39 has reached a sufficiently-elevated position to withdraw the depending rod 41 from between the opposed ends 36 of the latch fingers 34, the weighted body 33 will be released.

Once manner, body 33 is released, the force of the compressed spring 103 is effective for accelerating the weighted body rapidly downwardly so that it strikes the fluid-displacement piston 31 with considerable impact. in this maa substantial shock or pressure wave is developed in the fluent substance 23 which is effective for shifting the annular valve member 53 downwardly with sufficient force to break the shear pin 55. Once the shear pin 55 has failed, the upper valve member 53 will be moved downwardly a sufficient distance to bring its upper end below the seal 59 on the enlarged-diameter portion 58 of the axial tubular member 56 to open communication between the fluid chamber 30 and the filling ports 69 by way of the annular space between the axial tubular member and the inner wall of the intermediate portion of the elongated body 19. A sealing member 105 is arranged on the lower end of the valve member 53 for sealing engagement with the lowermost portion of the enlarged bore 27 to prevent loss of the fluent substance 23 through a pressure-equalizing port 106 provided into the enlargedbore below the upper sealing member 54.

Once the weighted body 33 has come to rest on top of the fluid-displacement piston 31, the weight of the body will be effective for moving the piston on downwardly through the fluid chamber 30 to forcibly displace a portion, as at 106, of the fluent substance 23 therefrom through the filling ports 69 and into the interior space within the expansible bag 18. it will, of

course, be appreciated that since the fluent substance 23 is initially at the hydrostatic pressure of the well bore fluids, the pressure developed by the weighted body 33 will be in addition to the hydrostatic pressure.

Thus, as the bag 18 is filling, the increased fluid pressure developed in .the fluent substance 23 by the weighted body 33 acting on the displacement piston 31 will be effective for expanding the bag outwardly with the portion 106 of the material and into contact with the walls of the well casing 14 immediately adjacent thereto. Expansion of the tubular bag 18 will, of course, be effective for drawing the unrestrained lower slidable collar 61 upwardly along the intermediate portion of the body 19 toward the still-latched upper collar 60. It should be noted that the latch fingers66 are biased inwardly with sufficient force that the expansion of the bag 18. will draw the lower collar 61 upwardly without releasing the enlarged heads 67 from the upper circum ferential, groove 68. 1

Accordingly, when the expansible bag 18 is fully expanded, it will initially be in a position in which its opposite ends substantially assume a generallyhemispherical configuration instead of the toroidal configuration shown in FIG. 3. At this point, there will still be a substantial volume ofthestill-fluent substance 23 remaining in the fluid chamber 30 so that the increased fluid pressure developed in the interior of the bag 18 by the weight of the body 33 acting on the piston 31 will expand the bag outwardly against the well casing 14 with a moderate lateral force.-Once the bag 18 is fully expanded, the discharge flow of the fluent substance 23 from the fluid chamber 30 will, of course,

temporarily cease and the displacement piston 31 and the weighted body 33 will come to rest at the upper fluid level of the fluent substance still remaining in the fluid chamber.

It will be recognized that the fluid pressure expanding the bag 18 outwardly will urge the exterior of the bag against the well casing 14 with a lateral force that is ef fective to frictionally secure the bag against longitudinal movement. Therefore, upon upward movement of the suspension cable 11, the upper housing section 17 and the elongated body 19 will initially be moved upwardly in relation to the stationary expanded bag 18 and the upper and lower slidable collars and 61. As will subsequently be explained in detail, this upward movement is effective for consecutively blocking further communication to the interior space in the expanded bag, actuating the biasing means 20, and ultimately freeing the housing section 17 from the elongated body 19.

First of all, upon upward movement of the elongated body 19, the inwardly-enlarged ends 67 of the latch fingers 66 will be cammed outwardly by the lower surface of the upper circumferential groove 68 to release the upper collar 60 for sliding movement in relation to the tool body. Thus, the continued upward travel of the elongated body 19 will be effective for carrying the fill ports 69 above the stationary upper collar 60 and then bringing the lower circumferential groove 72 up to or, perhaps, slightly above the heads 67 of the latch fingers 66. It will, of course, be recognized that once the lateral ports 69 pass above the fluid seal 62 on the upper collar 60, that portion 106 of the fluent substance 23 which has filled the expanded bag 18 will be sealingly enclosed therein. Moreover, once the lower circumferential groove 72 engages or passes above the latch fingers 66, the upper collar 60 cannot return upwardly in relation to the body to a position where the ports69 are again in communication with the interior space within the bag 18.

Furthermore, as the elongated body 19 is moved up wardly, the annular member 73 releasably coupled thereto will be carried upwardly toward the stationary lower collar 61 so as to bring the depending portion 82 thereof into contact with the inwardly-directed lip 83 of the ball-retainer sleeve 79. Then, as the elongated body 19 is moved further upwardly, the ball-retainer sleeve 79 will be halted and the continued movement of the annular member 73 will'ciarry the balls 76 upwardly into registration with the elongated slots 80. As previously described, once the balls 76 move into registration with the elongated slots 80, they will be free to move outwardly into the enlarged space therearound to disengage the balls from the circumferential groove 78 around the intermediate portion of the body 19.

Accordingly, once the balls 76 are disengaged from the circumferential groove 78, the compression biasing spring 74 will be released for forcibly urging the annular member 73 upwardly against the lower collar 61. Thus, as best seen in FIG. 3, once the compression spring 74 is released, it will impose a substantial upwardly-directed axial force against the lower end of the stationary expanded bag 18. This axial force will be effective for further increasing the fluid pressure of the still-fluent substance 106 trapped within the bag 18 which (if the enlarged heads 67 are below the groove 72) will initially move the upper collar 60 upwardly to accommodate the corresponding inward or upward depression of the lower end of the bag. Once, however, the upper collar 60 reaches a position on the intermediate portion of the body 19 where the latch fingers 66 are adjacent to the circumferential groove 72 just below the filling ports 69, the enlarged ends 67 thereof will be urged into the circumferential groove 72 to se cure the upper collar from further upward movement. Once the upper collar 72 is secured against further movement in relation to the elongated body 19, the upwardly-directed axial force imposed on the lower end of the bag 18 by the stout compression spring 74 will be effective for developing a downwardly-directed opposing or axial reaction force on the upper end of the expanded bag for depressing the central portions of the upper and lower ends of the bag inwardly so that, ultimately, the expanded bag will assume the generallytorodial configuration depicted in FlG. 3. The significance of this toroidal configuration is fully explained in US. Pat. No. 3,578,083 and, therefore, needs no further explanation.

Once the filling ports 69 are uncovered, the weighted body 33 will'resume downward movement of the piston 31 to displace the remainder of the fluent substance 23 contained within the fluid chamber 30 into the well bore annulus defined between the casing 14 and that portion of the elongated body 19 projecting upwardly above the expanded bag 18. In this manner, the remainder of the fluent substance 23 will be deposited on top of the expanded bag 18, as at 107, to further assure that an impermeable plug or barrier of substantial vertical height will be formed in the well bore 13 once the two portions of the fluent substance, as at 106 and 107, have ultimately expanded and hardened.

it will be appreciated, therefore, that once the wellcompletion tool has reached this particular stage of its operation, the fluent substance 106 trapped within the interior of the expanded bag 18 will be at a fluid pressure which is equalto the sum of the hydrostatic pressure of the fluids in the well bore 13,,the increased pressure developed by the displacement piston 31 once the bag is filled, and the further-increased pressure developed therein by the opposing axial forces imposed thereon by the released compression spring 74. As explained in US. Pat. No. 3,578,083, the perimeter of the bag 18 will be urged outwardly against the wall of the casing 14 with a total anchoring force that is proportionally related to the total pressure of the still-fluent substance 106 confined within the expanded bag. Accordingly, as shown in FIG. 3, once the bag 18 is securelyanchored in this manner, the upper housing portion 17 of the tool 10 is separated from the elongated body 19" by simply pulling further on the suspension cable 11 so that the heads 46 of the latch fingers 47 will be released from the circumferential groove 45 at the upper end of the elongated body once the displacement piston 31 has engaged the annular plate 50 and shifted the ring 48 below the heads. Then, as shown in FIG. 3, at some predetermined time thereafter, the timer mechanism 97 will function to release the tension spring 92 so as to shift the valve member 85 upwardly across the lower bypass ports 84 and into the valve seat 91 to permanently close the bypass passage 22.

Turning now to FIGS. 4 and 5, these two drawings respectively depict the valve member 85 of the bypass control means 21 as it will appear when it is first closed and as it will subsequently appear when the pressure in the well bore 13 below the expanded bag 18 is greater than the well bore pressure thereabove. Although the valve member 85 can, of course, be constructed in different ways and still accomplish the objects of the present invention, the valve member is preferably arranged as illustrated to facilitate its fabrication. Accordingly, in the preferred manner of providing a pressureactuated permanent closure of the bypass passage 22, the exterior of the valve body 86 is arranged to define oppositely-directed, inwardly-inclined surfaces 108 and 109 which are respectively extended from the central or mid-portion of the valve body and terminated at reduced-diameter end portions 110 and 111 at each end of the valve body. For reasons that will be subsequently explained, the valve member 85 further includes a pair of frustoconical rings 113 and 114 having inclined or uniformly-tapered exterior surfaces, as at 115 and 116, which are sealingly fitted or mounted on the reduced-diameter end portions 110 and 111 of the valve body 86, respectively, and oppositely oriented so as to position their tapered exterior surfaces facing and diverging away from the inclined surfaces 108 and 109. Resilient sealing members, such as the pair of typical O-rings 87 and 88 of an elastomeric material, are respectively disposed around the reduced end portions 110 and 111 within the outwardly-diverging circumferential grooves respectively defined between the opposed upper inclined surfaces 108 and 115 and the opposed lower inclined surfaces 109 and 116.

As has been typical heretofore, the O'rings 87 and 88 are, of course, cooperatively sized for effecting sealing engagement with the valve seat 91 for blocking fluid communication through the bypass 22 once the valve member 85 is moved to the position depicted in FIG. 4 and is straddling the lateral ports 84. Although the cooperation of the O-rings 87 and 88 will suffice to initially close the lower bypass ports 84, those skilled in the art will appreciated that even the most durable elastomeric O-rings will ultimately deteriorate under even the most-favorable well bore conditions. The degeneration of such sealing elements 87 and 88 will, of course, be accelerated in the presence of corrosive well bore liquids and gases as well as by elevated temperatures. Thus, irrespective of the quality of the remainder of the tool 10, the permanence of the plug in the well bore 13 represented by the cement 106 in the expanded bag 18, the body 19 and the residual quantity of cement 107 deposited on top of the tool will be directly dependent upon the effective life of the O-rings 87 and 88 unless additional measures are provided.

Accordingly, in keeping with the objects of the present invention, the new and improved bypass control means 21 further include supplemental self-energizing sealing elements 117-120 of a corrosion-resistant expansible or ductile material which are respectively mounted around the valve body 86 on opposite sides of the O-rings 87 and 88 and cooperatively arranged to be selectively expanded into sealing engagement between the valve body and the valve seat 91. In the preferred embodiment of the valve member 85, this is accomplished by forming each of the supplemental sealing elements 117-120 as a cylindrical ring having a tapered internal bore or surface, as at 121, which is cooperatively shaped so as to complementally fit the inclined camming surface, as at 115, on which that particular ring is mounted. To achieve a permanent sealing engagement between the valve body 86 and the valve seat 91, the rings 117-120 are preferably formed of a ductile corrosion-resistant material having a relatively-low modulus of elasticity, such as lead, copper, brass or titanium, which is selected to be readily yieldable or radially-expansible under axial or longitudinal loading as well as capable of withstanding or resisting attack or degradation by exposure to corrosive well bore fluids and elevated well bore temperatures.

Although other constructional arrangements can be devised without departing from the scope of the present invention, it is preferred to form the valve member 85 as illustrated with the valve body 86 being separated from the two outer rings 113 and 114. Thus, to assemble the valve member 85, the O-rings 87 and 88 and the expansible rings 117-120 are first placed on the end portions 110 and 111 and then the outer rings 113 and 114 are fitted on the extremities of the end portions of the body 86. To assure that the assembled valve member 85 remains intact, it is preferred to upset the ends of the valve body 86 as at 122 and 123.

It will be appreciated from FIG. 4 that once the timing mechanism 97 has released the valve member 85 for movement to its illustrated final position, the O- rings 87 and 88 will provide an effective fluid seal between the valve seat 91 and the valve body 86 for blocking further fluid communication through the lateral ports 84. However, in keeping with the objects of the present invention, the expansible rings 117-120 are cooperable with the O-rings 87 and 88 as well as their respectively-associated inclined surfaces 108, 109, 115 and 116 for ultimately providing permanent seals on opposite sides of the lateral ports 84.

Once the valve member 85 is closed, it will be appreciated that there will ordinarily be a pressure differential between the fluids in the well bore 13 above the expanded bag 18 (as shown in FIG. 3) and the well bore fluids below the tool 10. Although such a pressure differential can exist in either direction and the new and improved bypass control meansZl are cooperatively arranged for handling either situation, FIG. 5 depicts the unique operation of the bypass control means in response to the pressure in the well bore 13 below the expanded bag 18 being greater than the pressure thereabove.

It will, or course, be appreciated that in this situation, the bypass passage 22 will be at a lower pressure than the pressure imposed on the exterior of the tool body 19 adjaeentto the ports 84. Thus, the pressure imposed in the small annular space 124 defined around the valve body 86 and between the O-rings 87 and 88 will be greater than the pressure in the body bore 71 outside of this small annular space. Accordingly, the resulting pressure differential will be effective for urging the O- rings 87 and 88 apart --0 that is to say, upwardly and downwardly respectively with oppositely-directed longitudinal forces that are proportional to the magnitude of the pressure differential. Asa result, the two outer ductile rings 117 and 120 will be respectively driven up their associated outer inclinedsurfaces 115 and 116 by the oppositely-moving O-rings 87 and 88. This action will, therefore, cause the ductile rings 117 and 120 to, be expanded into firm seating engagement between the adjacent portions of the valve seat 91 and the outer inclined surfaces 115 and 116, respectively, to provide a permanent metal-to-metal seal at each end of the valve body 86.

A similar action will occur should the well bore pressure above the expanded bag 18 be greater than that below. Considering FIG. 4 again, it will be recognized that in this situation, the pressure in the longitudinal bore 71 will be greater than the pressure in the small annular space 124 defined around the mid-portion of the valve body 86 and between the O-rings 87 and 88. Accordingly, as the O-rings 87 and 88 are moved toward one another by this pressure differential, the 0- rings will respectively urge the inner ductile rings 118 and 119 up their associated inner inclined surfaces 108 and 109 to establish a tight metal-t-o-metal seal between the adjacnet portions of the valve body 86 and the valve seat 91.

It should be noted as well that once the ductile rings 117 and (or 118 and 119) are moved into seating engagement with the valve seat 91, they will be too tightly wedged to ever return to their original positions even if there is a change in the pressure conditions in the well bore 13. However, should there be a subsequent increase in the magnitude of the pressure differential which initially seated the dluctile rings 117 and 120 (or 118 and 119), the previously-seated rings could possibly be moved into even firmer seating engagement with the valve seat 91 if the increase was suf ficient to require additional sealing capability for permanently blocking the bypass passage 22.

Accordingly, it will be appreciated that the present invention has provided a new and improved well tool which is uniquely arranged for permanently plugging a well bore with a cementitious substance. To accomplish this, the new and improved well tool includes a body carrying an extendible member, such as an expansible tubular bag, which is cooperatively arranged to be extended into engagement with the well bore walls for supporting a cementitious substance until it has hardened into an annular plug around the body. A bypass passage in the body is initially left open until such time that the plugging substance had hardened and is then closed by selective movement of a unique valvemember into a valve seat for blocking the passage. By means of a combination of typical elastomeric sealing members and sealing members of a corrosion-resistant ductilemetal which are cooperatively arranged on inclined surfaces on the valve body, pressure differentials acting across the valve member will be effective for urging the ductile sealing members into metal-to-metal engagement between the valve seat and the valve body to permanently close the bypass passage even though the elastomeric sealing members subsequently degenerate.

While only a particular embodiment of the present invention has been shown and described, it is apparent that changes and modifications may be made without departing from this invention in its broader aspects; and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

a What is claimed is:

1. Apparatus adapted for plugging a well bores and comprising:

a tool body adapted to be suspended in a well bore;

first means cooperativelyarranged on said tool body and including extendible support means adapted for extension outwardly from said tool body for carrying an initially-fluent hardenable substance until it is hardened into a solidified mass between an adjacent well bore wall and saidtool body; fluid-bypass means cooperatively arranged on said tool body and including a fluid passage extending above and below said support means and adapted for bypassing well bore fluids as a fluent substance carried by said support means hardens; and bypass control means adapted for permanently closing said fluid passage after a fluent substance on said support means has hardened and including means providing a valve seat in said fluid passage, a valve body adapted for movement from an initial passage-opening position to a final passage-closing position within said valve seat, valve-actuating means adapted for moving said valve body from its said initial position to its said final position, at least one resilient sealing member cooperatively arranged between said valve body and said valve seat and adapted for effecting at least temporary sealing engagement therebetween once said valve body is moved to its said final position, at least one sealing member of a ductile metal cooperatively arranged between said resilient sealing member and said valve seat, and camming means cooperatively arranged between said ductile metal sealing member and said valve seat for permanently seating said ductile metal sealing member'between said valve body and said valve seat in response to a pressure differential urging said resilient sealing member against said ductile metal sealing member once said valve body is moved to its said final position.

2. The apparatus of claim 1 wherein said valveactuating means include means cooperatively associated with said valve body and adapted for moving said valve body to its said final position only after the elapse of a period of time greater than the time interval believed to be sufficient for a fluent hardenable substance carried by said extended support means to have substantially hardened.

3. The apparatus of claim 1 wherein said support means include a tubular bag ofa flexible material cooperatively arranged around said tool body and adapted for expansion into engagement with an adjacent well bore wall upon receiving a supply of a fluent hardenable substance; and said first means further include means for retaining said tubular bag expanded until a fluent hardenable substance carried thereby has hardened. y

4. The apparatus of claim 3 further including: selectively-operable fluid-displacement means releasably coupled to said tool body and adapted to discharge a first quantity of a fluent hardenable substance into said tubular bag for expanding said bag into engagement with an adjacent well bore wall; and g 7 means operable upon the discharge of said first quantity of a fluent hardenable substance into said tubular bag for uncoupling said fluid-displacement means from said tool body to discharge a second quantity of a fluent hardenable substance onto said expanded tubular bag. 5. The apparatus of claim 1 further including: selectively-operable fluid-displacement means coupled to said tool body and adapted to discharge a fluent hardenable substance onto said extended support means. 6. The apparatus of claim 1 further including: selectively-operable fluid-displacement means releasably coupled to said tool body and adapted to discharge a fluent hardenable substance onto said support means; and

means operable upon the discharge of a fluent hardenable substance onto said support means for uncoupling said fluid-displacement means from said tool body.

7. The apparatus of claim 1 wherein said resilient sealing member and said ductile metal sealing member are movably disposed around said valve body; and said camming means include an outwardly-tapered surface around said valve body and extending away from said ductile metal sealing member for tightly expanding said ductile metal sealing member into engagement with said valve seat as a pressure differential urges said resilient sealing member against said ductile metal sealing member to drive said .ductile metal sealing member over said outwardly-tapered surface.

8. The apparatus of claim 7 wherein said ductile metal sealing member is formed of a metal selected from the group consisting of copper, brass, lead or titanium.

9. Apparatus adapted for plugging a well bore and comprising:

a tool body adapted to be suspended in a well bore and including a fluid bypass passage having a valve seat defined therein and extending between longitudinally-spaced openings;

extendible support means cooperatively arranged around said tool body between said openings and adapted to be extended outwardly therefrom for carrying an initially-fluent hardenable wellplugging substance as it hardens into a solidified mass between an adjacent well bore wall and said tool body; and

bypass-control means adapted for permanently closing said bypass passage after a fluent substance carried by said support means has at least substantially hardened and including a valve body adpated for movement from an initial passage-opening position to a final passage-closing position in said valve seat, valve-actuating means adapted for selectively moving said valve body to its said final position, first sealing means of a resilient non-metallic material cooperatively arranged for effecting at least temporary sealing engagement between said valve seat and said valve body upon movement thereof to its said final position, second sealing means of a duetile metal cooperatively arranged on said valve body for movement therealong by said first sealing means after said valve body is in its said final position and in response to a pressure differential urging said first sealing means against one side of said second sealing means, and camming means cooperatively arranged on said valve body adjacent to the other side of said second sealing means and adapted for progressively expanding said second sealing means into sealing engagement with said valve seat with a force proportional to the magnitude of such a pressure differential.

10. The apparatus of claim 9 wherein said first sealing means are on said valve body.

11. The apparatus of claim 9 wherein said second sealing means include a ductile metal ring having a tapered bore; and said camming means include an outwardly-tapered surface on said valve bodycomplemental to said tapered bore.

to one another, said second sealing means include first and second ductile metal rings adjacent to said first and second tapered surfaces and respectively having tapered bores complemental thereto; and said first sealing means include at least one elastomeric sealing ring movably disposed around said valve body between said first and second ductile metal rings and cooperatively arranged for movement toward said first metal ring in response to a pressure differential acting in one direction across said body and for movement toward said second metal ring in response to a pressure acting in the opposite direction across said valve body.

13. The apparatus of claim 9 wherein said camming means include first and second outwardly-tapered surfaces around said valve body and diverging in relation to one another; said second sealing means include first and second ductile metal rings adjacent to said first and second tapered surfaces and respectively having tapered bores complemental thereto; and said first sealing means include first and second elastomeric sealing rings movably disposed around said valve body respectively adjacent to said first and second ductile metal rings and cooperatively arranged for movement theretoward in response to a pressure differential acting on said first and second elastomeric rings and urging them respectively toward said first and second ductile metal rings and tapered surfaces.

14. The apparatus of claim 13 wherein said first and second tapered surfaces are respectively adjacent to the opposite ends of said valve body, said first and second elastomeric rings are adjacent to the mid-portion of said valve body, said first ductile metal ring is disposed between said first tapered surface and said first elastomeric ring, and said second ductile metal ring is disposed between said second tapered surface and said second elastomeric ring.

15 The apparatus of claim 13 wherein said firstand second elastomeric rings are respectively spaced on opposite sides of the mid-portion of said valve body, said first and second tapered surfaces are adjacent to said mid-portion of said valve body, said first ductile metal ring is disposed between said first tapered surface and said first elastomeric ring, and said second ductile metal ring is disposed between said tapered surface and said second elastomeric ring. a

16. The apparatus of claim 9 wherein said support means include a tubular bag of a flexible material cooperatively arranged around said tool body and adapted for expansion against an adjacent well bore wall upon receiving a supply of a fluent hardenable substance, and further including:

i first means adapted for selectively supplying a fluent hardenable substance to said tubular bag; and

second means adapted for retaining said tubular bag expanded until a fluent hardenable substance carried thereby has hardened.

17. The apparatus of claim 16 wherein said first means include selectively-operable fluid-displacement means releasably coupled to said tool body and adapted to discharge a fluent hardenable substance into said tubular bag for expanding said tubular bag, and means operable upon the discharge of a fluent hardenable substance into said tubular bag for uncoupling said fluid-displacement means from said tool body.

18. The apparatus of claim 9 wherein one of said opening is a lateral port in said tool body and intersecting said valve seat, and further including:

an equalizing passage through said valve body adapted for equalizing oppositely-directed pressure forces acting thereon.

19. Apparatus adapted for plugging a well bore and comprising:

a tool body adapted to be suspended in a well bore and including a fluid bypass passage extending between longitudinally-spaced openings and having a cylindrical valve seat defined therein intersected by one of said openings;

a tubular bag of a flexible material cooperatively arranged around said tool body between said openings and adapted for expansion into anchoring and sealing engagement with an adjacent well bore wall upon being filled with a fluent hardenable substance;

means operable upon expansion of said tubular bag for retaining said tubular bag expanded as a fluent hardenable substance carrier thereby hardens; and bypass-control means adapted for permanently closing said bypass passage after a fluent substance car ried by said expanded tubular bag has at least substantially hardened and including a substantially cylindrical valve body adapted for axial movement from an initial position to a final position in said valve seat, means providing first and second axially-spaced circumferential grooves around said valve body and respectively defined by first and second pairs of outwardly-diverging oppositelydirected inner and outer tapered surfaces, first and second elastomeric sealing members respectively mounted around said valve body within said first and second circumferential grooves and cooperatively arranged for sealing engagement with said valve seat upon movement of said valve body to its said final position, a first pair of expansible sealing members of a ductile metal respectively arranged around said valve body within said first and second circumferential grooves and respectively having an internally-tapered bore complementary with said first and second outer tapered surfaces for progressively expanding said first metal sealing members into permanent sealing engagement with said valve seat after movement of said valve body to its said final position and in response to the application of an increased pressure in said! one opening respectively urging said first and second elastomeric sealing members outwardly toward said first metal sealing members, a second pair of expansible sealing members of a ductile metal respectively arranged around said valve body within said first and second circumferential grooves and respectively having an internally-tapered bore complementary with said first and second inner tapered surfaces for progressively expanding said second metal sealing members into permanent sealing engagement with said a valve seat after movement of said valve body to its said final position and in response to the application of an increased pressure in said bypass passage respectively urging said first and second elastomeric sealing members inwardly toward said second metal sealing members, and valve-actuating means for selectively moving said valve body to its said final position.

20. The apparatus of claim 19 wherein said valveactuating means include biasing means urging said valve body toward its said final position, and means adapted for releasably restraining said valve body from movement away from its said initial position until after said tubular bag has been expanded.

21. The apparatus of claim 20 wherein said means releasably restraining said valve body including latching means releasably coupled to said valve body and normally retaining said valve body in its said initial position against said biasing means, and means cooperable with said latching means for uncoupling said latching means from said valve body after the elapse of a selected time interval.

uppermost one of said openings. 

1. Apparatus adapted for plugging a well bore and comprising: a tool body adapted to be suspended in a well bore; first means cooperatively arranged on said tool body and including extendible support means adapted for extension outwardly from said tool body for carrying an initially-fluent hardenable substance until it is hardened into a solidified mass between an adjacent well bore wall and said tool body; fluid-bypass means cooperatively arranged on said tool body and including a fluid passage extending above and below said support means and adapted for bypassing well bore fluids as a fluent substance carried by said support means hardens; and bypass control means adapted for permanently closing said fluid passage after a fluent substance on said support means has hardened and including means providing a valve seat in said fluid passage, a valve body adapted for movement from an initial passage-opening position to a final passage-closing position within said valve seat, valve-actuating means adapted for moving said valve body from its said initial position to its said final position, at least one resilient sealing member cooperatively arranged between said valve body and said valve seat and adapted for effecting at least temporary sealing engagement therebetween once said valve body is moved to its said final position, at least one sealing member of a ductile metal cooperatively arranged between said resilient sealing member and said valve seat, and camming means cooperatively arranged between said ductile metal sealing member and said valve seat for permanently seating said ductile metal sealing member between said valve body and said valve seat in response to a pressure dIfferential urging said resilient sealing member against said ductile metal sealing member once said valve body is moved to its said final position.
 2. The apparatus of claim 1 wherein said valve-actuating means include means cooperatively associated with said valve body and adapted for moving said valve body to its said final position only after the elapse of a period of time greater than the time interval believed to be sufficient for a fluent hardenable substance carried by said extended support means to have substantially hardened.
 3. The apparatus of claim 1 wherein said support means include a tubular bag of a flexible material cooperatively arranged around said tool body and adapted for expansion into engagement with an adjacent well bore wall upon receiving a supply of a fluent hardenable substance; and said first means further include means for retaining said tubular bag expanded until a fluent hardenable substance carried thereby has hardened.
 4. The apparatus of claim 3 further including: selectively-operable fluid-displacement means releasably coupled to said tool body and adapted to discharge a first quantity of a fluent hardenable substance into said tubular bag for expanding said bag into engagement with an adjacent well bore wall; and means operable upon the discharge of said first quantity of a fluent hardenable substance into said tubular bag for uncoupling said fluid-displacement means from said tool body to discharge a second quantity of a fluent hardenable substance onto said expanded tubular bag.
 5. The apparatus of claim 1 further including: selectively-operable fluid-displacement means coupled to said tool body and adapted to discharge a fluent hardenable substance onto said extended support means.
 6. The apparatus of claim 1 further including: selectively-operable fluid-displacement means releasably coupled to said tool body and adapted to discharge a fluent hardenable substance onto said support means; and means operable upon the discharge of a fluent hardenable substance onto said support means for uncoupling said fluid-displacement means from said tool body.
 7. The apparatus of claim 1 wherein said resilient sealing member and said ductile metal sealing member are movably disposed around said valve body; and said camming means include an outwardly-tapered surface around said valve body and extending away from said ductile metal sealing member for tightly expanding said ductile metal sealing member into engagement with said valve seat as a pressure differential urges said resilient sealing member against said ductile metal sealing member to drive said ductile metal sealing member over said outwardly-tapered surface.
 8. The apparatus of claim 7 wherein said ductile metal sealing member is formed of a metal selected from the group consisting of copper, brass, lead or titanium.
 9. Apparatus adapted for plugging a well bore and comprising: a tool body adapted to be suspended in a well bore and including a fluid bypass passage having a valve seat defined therein and extending between longitudinally-spaced openings; extendible support means cooperatively arranged around said tool body between said openings and adapted to be extended outwardly therefrom for carrying an initially-fluent hardenable well-plugging substance as it hardens into a solidified mass between an adjacent well bore wall and said tool body; and bypass-control means adapted for permanently closing said bypass passage after a fluent substance carried by said support means has at least substantially hardened and including a valve body adpated for movement from an initial passage-opening position to a final passage-closing position in said valve seat, valve-actuating means adapted for selectively moving said valve body to its said final position, first sealing means of a resilient non-metallic material cooperatively arranged for effecting at least temporary sealing engagement between said valve seat and said valve body Upon movement thereof to its said final position, second sealing means of a ductile metal cooperatively arranged on said valve body for movement therealong by said first sealing means after said valve body is in its said final position and in response to a pressure differential urging said first sealing means against one side of said second sealing means, and camming means cooperatively arranged on said valve body adjacent to the other side of said second sealing means and adapted for progressively expanding said second sealing means into sealing engagement with said valve seat with a force proportional to the magnitude of such a pressure differential.
 10. The apparatus of claim 9 wherein said first sealing means are on said valve body.
 11. The apparatus of claim 9 wherein said second sealing means include a ductile metal ring having a tapered bore; and said camming means include an outwardly-tapered surface on said valve body complemental to said tapered bore.
 12. The apparatus of claim 9 wherein said camming means include first and second outwardly-tapered surfaces around said valve body and diverging in relation to one another, said second sealing means include first and second ductile metal rings adjacent to said first and second tapered surfaces and respectively having tapered bores complemental thereto; and said first sealing means include at least one elastomeric sealing ring movably disposed around said valve body between said first and second ductile metal rings and cooperatively arranged for movement toward said first metal ring in response to a pressure differential acting in one direction across said body and for movement toward said second metal ring in response to a pressure acting in the opposite direction across said valve body.
 13. The apparatus of claim 9 wherein said camming means include first and second outwardly-tapered surfaces around said valve body and diverging in relation to one another; said second sealing means include first and second ductile metal rings adjacent to said first and second tapered surfaces and respectively having tapered bores complemental thereto; and said first sealing means include first and second elastomeric sealing rings movably disposed around said valve body respectively adjacent to said first and second ductile metal rings and cooperatively arranged for movement theretoward in response to a pressure differential acting on said first and second elastomeric rings and urging them respectively toward said first and second ductile metal rings and tapered surfaces.
 14. The apparatus of claim 13 wherein said first and second tapered surfaces are respectively adjacent to the opposite ends of said valve body, said first and second elastomeric rings are adjacent to the mid-portion of said valve body, said first ductile metal ring is disposed between said first tapered surface and said first elastomeric ring, and said second ductile metal ring is disposed between said second tapered surface and said second elastomeric ring.
 15. The apparatus of claim 13 wherein said first and second elastomeric rings are respectively spaced on opposite sides of the mid-portion of said valve body, said first and second tapered surfaces are adjacent to said mid-portion of said valve body, said first ductile metal ring is disposed between said first tapered surface and said first elastomeric ring, and said second ductile metal ring is disposed between said tapered surface and said second elastomeric ring.
 16. The apparatus of claim 9 wherein said support means include a tubular bag of a flexible material cooperatively arranged around said tool body and adapted for expansion against an adjacent well bore wall upon receiving a supply of a fluent hardenable substance, and further including: first means adapted for selectively supplying a fluent hardenable substance to said tubular bag; and second means adapted for retaining said tubular bag expanded until a fluent hardenable substance carried thereby has hardened.
 17. The apparatus of claim 16 wherein said first means include selectively-operable fluid-displacement means releasably coupled to said tool body and adapted to discharge a fluent hardenable substance into said tubular bag for expanding said tubular bag, and means operable upon the discharge of a fluent hardenable substance into said tubular bag for uncoupling said fluid-displacement means from said tool body.
 18. The apparatus of claim 9 wherein one of said opening is a lateral port in said tool body and intersecting said valve seat, and further including: an equalizing passage through said valve body adapted for equalizing oppositely-directed pressure forces acting thereon.
 19. Apparatus adapted for plugging a well bore and comprising: a tool body adapted to be suspended in a well bore and including a fluid bypass passage extending between longitudinally-spaced openings and having a cylindrical valve seat defined therein intersected by one of said openings; a tubular bag of a flexible material cooperatively arranged around said tool body between said openings and adapted for expansion into anchoring and sealing engagement with an adjacent well bore wall upon being filled with a fluent hardenable substance; means operable upon expansion of said tubular bag for retaining said tubular bag expanded as a fluent hardenable substance carrier thereby hardens; and bypass-control means adapted for permanently closing said bypass passage after a fluent substance carried by said expanded tubular bag has at least substantially hardened and including a substantially-cylindrical valve body adapted for axial movement from an initial position to a final position in said valve seat, means providing first and second axially-spaced circumferential grooves around said valve body and respectively defined by first and second pairs of outwardly-diverging oppositely-directed inner and outer tapered surfaces, first and second elastomeric sealing members respectively mounted around said valve body within said first and second circumferential grooves and cooperatively arranged for sealing engagement with said valve seat upon movement of said valve body to its said final position, a first pair of expansible sealing members of a ductile metal respectively arranged around said valve body within said first and second circumferential grooves and respectively having an internally-tapered bore complementary with said first and second outer tapered surfaces for progressively expanding said first metal sealing members into permanent sealing engagement with said valve seat after movement of said valve body to its said final position and in response to the application of an increased pressure in said one opening respectively urging said first and second elastomeric sealing members outwardly toward said first metal sealing members, a second pair of expansible sealing members of a ductile metal respectively arranged around said valve body within said first and second circumferential grooves and respectively having an internally-tapered bore complementary with said first and second inner tapered surfaces for progressively expanding said second metal sealing members into permanent sealing engagement with said valve seat after movement of said valve body to its said final position and in response to the application of an increased pressure in said bypass passage respectively urging said first and second elastomeric sealing members inwardly toward said second metal sealing members, and valve-actuating means for selectively moving said valve body to its said final position.
 20. The apparatus of claim 19 wherein said valve-actuating means include biasing means urging said valve body toward its said final position, and means adapted for releasably restraining said valve body from movement away from its said initial position until after said tubular bag has been expanded.
 21. The apparatus of claim 20 wherein said means releasably restraining said valve body including latching means rEleasably coupled to said valve body and normally retaining said valve body in its said initial position against said biasing means, and means cooperable with said latching means for uncoupling said latching means from said valve body after the elapse of a selected time interval.
 22. The apparatus of claim 19 further including: selectively-operable fluid-displacement means releasably coupled to said tool body and adapted to discharge a first quantity of a fluent hardenable substance into said tubular bag for filling said tubular bag until it is expanded; and means operable upon filling of said tubular bag for uncoupling said fluid-displacement means from said tool body and discharging an additional quantity of a fluent hardenable substance onto said expanded bag and around said tool body below the uppermost one of said openings. 